Astro Compass Mk II

Accession Number REL32930
Collection type Technology
Object type Technology
Physical description Aluminium, Brass, Canvas, Felt, Glass, Liquid, Metal, Paper, Perspex, Wood
Date made c 1943
Conflict Second World War, 1939-1945

The compass consists of a triangular base with three tubular legs. A mid-section comprises a circular aluminium disc with North, South, East, and West marked, as well as 360 degree markers. Engraved on the disc is A.M, ASTRO COMPASS MK II 6.A/1174 2. X Attached to the side of the disc is a square piece of metal containing two spirit levels, one vertical, the other horizontal. Engraved on the spirit level is: TRUE COURSE and an arrow. Two brackets are fixed to the mid section of the disc. Engraved on the side of one bracket is: 'LEVEL SET LAT, SET L.H.A BODY, ALIGN ON BODY, READ TRUE COURSE'. Attached to the other brackets are adjustment knobs for the compass. Bolted to the top of the brackets is a tubular piece of metal. Engraved on this is 'N. LAT. WHITE, S. LAT. RED, ALL BEARINGS WHITE'. Attached vertically to the top of the tubular section is a square piece of metal with a rounded top. Bearings have been engraved around the circular top, with a moveable indicator arrow. Attached to the circular top just beneath the indicator arrow is a rectangular piece of metal with two side pieces and no top. White Perspex, glued to the base of the rectangle reads DECLINATION and is slightly radio-active (not dangerous level). The compass is housed in its original wooden box. The box is rectangular with a hinged lid featuring a pair of brass screw hinges, and is painted in now chipped overall olive/khaki green. Stencilled on the top, front and back of the box is a white rectangle with 'DELICATE INSTRUMENT TO BE HANDLED WITH GREAT CARE'. On the side of the lid is also stencilled 'ASTRO COMPASS MK II'. A paper sticker on the inside of the lid is marked with 'PACKING SET COURSE TO "S" AND LAT. TO "9" AND PLACE IN BOX WITH LEVELS DOWN'. To the left of this sticker are the remnants of a stamped oval marking featuring the date '16 FEB 1943' along with '1393' in smudged white chalk . A 105 mm x 60 mm faded yellow paper envelope is inside the box, this contains a pair of 3 mm diameter screws, a black 'U' shaped metal bracket with two holes and a semi-circular 16 mm x 8 mm piece of clear perspex. Attached to the right and left sides of the box is a canvas handle, secured by two screws on each side. The front of the lid has two screws sticking out slightly which two hooks, secured below the screws, latch over to keep the lid closed. Painted on the left side of the box in yellow paint is '992', and on the top of the lid in white paint is '798'. The inside of the box is painted grey and has green felt supports to secure the compass when it is not in use. The compass when stored is laid horizontally across the bottom of the box.

History / Summary

Astro Compasses were used during the Second World War by pilots and navigators to calculate true North and heading by the sun or stars. Astro compasses of this size and type were used onboard larger multi-crewed Allied aircraft such as the Avro Lancaster, Bristol Beaufort and Consolidated Liberator.